1998 Cadillac Deville purpose of pellets in coolant

If you are due for new antifreeze, it wouldn't hurt to flush it out first.

The purpose of the pellets is to add a conditioner/stop leak into the system as a preventative measure. This is especially good for aluminum engines as aluminum can be a porous material and have very small pin holes left from molding processes that can cause problems. ( I was in diesel/gas engine manufacturing engineering for 37+ years. )

Do not use them, they clogg stuff up more than doing anything, use liquid stuff, it really doesnt dissulve